The cause of migraine is not clear. It is suspected that increased blood stream due to expansion of head or cervix blood vessels caused by hormone unbalance, and muscle contraction in the area is the cause of migraine.
For the treatment of migraine, analgesics for an internal application, which contain ergotamine tartrate, dimethothiazine mesylate, caffeine, etc., as an active ingredient are used. However, such a drug is often administered for long term and therefore, there is a possibility to induce side effects such as, anaphylaxis, insomnia, or gastrointestinal disorder.
Accordingly, various preparations for dermal applications for treating migraine have been worked out.
For example, in Japanese Patent Publication B 6-67835, a composition where methysergide, an anti-serotonin, is dispersed in a hydrophilic polymer for systemic dermal application to prevent migraine is disclosed. Furthermore, in Japanese Patent Publication A Tokuhyo Hei 8-509749, a dermally therapeutic system containing sumatriptan, which is useful for migraine, cluster headache, etc., is disclosed.
However, these preparations for dermal application have a possibility to induce side effects, such as skin irritation, etc., by administering them for long term and therefore, these preparations are not favorable.
In addition, it is known that essential oils alleviate headache when used as an aromatherapy, but they are not simple to use.
The present inventors have extensively studied in order to obviate the above mentioned demerits, and as a result, have unexpectedly found that migraine can be alleviated by dermally administering to a human a drug containing l-menthol and an essential oil as active ingredients. Thus, the present invention has been completed.